diff --git a/main/command/BasicCommands.scala b/main/command/BasicCommands.scala
index c0f435816..18fe40d90 100644
--- a/main/command/BasicCommands.scala
+++ b/main/command/BasicCommands.scala
@@ -169,7 +169,7 @@ object BasicCommands
 		val name = token(OpOrID.examples( aliasNames(s) : _*) )
 		val assign = token(OptSpace ~ '=' ~ OptSpace)
 		val sfree = removeAliases(s)
-		val to = matched(sfree.combinedParser, partial = true) | any.+.string
+		val to = matched(sfree.combinedParser, partial = true).failOnException | any.+.string
 		val base = (OptSpace ~> (name ~ (assign ~> to.?).?).?)
 		applyEffect(base)(t => runAlias(s, t) )
 	}
diff --git a/sbt/src/sbt-test/actions/aliasrc/.sbtrc b/sbt/src/sbt-test/actions/aliasrc/.sbtrc
new file mode 100644
index 000000000..3d7d3773e
--- /dev/null
+++ b/sbt/src/sbt-test/actions/aliasrc/.sbtrc
@@ -0,0 +1 @@
+alias info= set logLevel := Level.Info
diff --git a/sbt/src/sbt-test/actions/aliasrc/test b/sbt/src/sbt-test/actions/aliasrc/test
new file mode 100644
index 000000000..2ae698547
--- /dev/null
+++ b/sbt/src/sbt-test/actions/aliasrc/test
@@ -0,0 +1 @@
+> info
diff --git a/util/complete/Parser.scala b/util/complete/Parser.scala
index 7f0fba5db..a10d1bdcb 100644
--- a/util/complete/Parser.scala
+++ b/util/complete/Parser.scala
@@ -45,6 +45,9 @@ sealed trait RichParser[A]
 
 	/** Uses the specified message if the original Parser fails.*/
 	def !!!(msg: String): Parser[A]
+	/** If an exception is thrown by the original Parser,
+	* capture it and fail locally instead of allowing the exception to propagate up and terminate parsing.*/
+	def failOnException: Parser[A]
 	
 	def unary_- : Parser[Unit]
 	def & (o: Parser[_]): Parser[A]
@@ -173,6 +176,8 @@ object Parser extends ParserMain
 
 	def onFailure[T](delegate: Parser[T], msg: String): Parser[T] =
 		if(delegate.valid) new OnFailure(delegate, msg) else failure(msg)
+	def trapAndFail[T](delegate: Parser[T]): Parser[T] =
+		delegate.ifValid( new TrapAndFail(delegate) )
 
 	def zeroOrMore[T](p: Parser[T]): Parser[Seq[T]] = repeat(p, 0, Infinite)
 	def oneOrMore[T](p: Parser[T]): Parser[Seq[T]] = repeat(p, 1, Infinite)
@@ -233,6 +238,7 @@ trait ParserMain
 		def <~[B](b: Parser[B]): Parser[A] = (a ~ b) map { case av ~ _ => av }
 		def ~>[B](b: Parser[B]): Parser[B] = (a ~ b) map { case _ ~ bv => bv }
 		def !!!(msg: String): Parser[A] = onFailure(a, msg)
+		def failOnException: Parser[A] = trapAndFail(a)
 	
 		def unary_- = not(a)
 		def & (o: Parser[_]) = and(a, o)
@@ -425,6 +431,18 @@ private final case class Invalid(fail: Failure) extends Parser[Nothing]
 	def valid = false
 	def ifValid[S](p: => Parser[S]): Parser[S] = this
 }
+
+private final class TrapAndFail[A](a: Parser[A]) extends ValidParser[A]
+{
+	def result = try { a.result } catch { case e: Exception => None }
+	def resultEmpty = try { a.resultEmpty } catch { case e: Exception => fail(e) }
+	def derive(c: Char) = try { trapAndFail(a derive c) } catch { case e: Exception => Invalid(fail(e)) }
+	def completions(level: Int) = try { a.completions(level) } catch { case e: Exception => Completions.nil }
+	override def toString = "trap(" + a + ")"
+	override def isTokenStart = a.isTokenStart
+	private[this] def fail(e: Exception): Failure = mkFailure(e.toString)
+}
+
 private final class OnFailure[A](a: Parser[A], message: String) extends ValidParser[A]
 {
 	def result = a.result